Thermic lance

ABSTRACT

A thermic lance which is operated by gaseous combustion and serves for forming openings, cavities or grooves in hard material such as concrete, stone, building walls and the like. The lance is equipped with a steel tube packed with a plurality of steel rods. Oxygen is passed through the tube from one end and the lance is ignited at the other end to produce an intense heat source that is applied to the material to be cut. Both the tube and rods become consumed during burning out process. The enclosing tube has with the exception of its ends a crosssectional shape which is other than circular. For securing the rods in the tube a flat arcuate divergence is provided in the tube and the rods near the gas connecting end part of the lance. Formation of the divergent zone and deformation of the tube in a non-circular cross-sectional shape is effected simultaneously by a single press operation.

Unite States Patent 1 Brandenberger June 12, 1973 THERMIC LANCE [75]Inventor: Ernst Brandenberger, Wetzikon,

Switzerland [73] Assignee: Kubatec Kunststoff-und Bautechnik AG,Triesen, Fla. a part interest [22} Filed: Jan. 26, 1972 [21] Appl. No.:220,787

[30] Foreign Application Priority Data Feb. 5, 1971 Switzerland 1725/71[52] U.S. Cl. 110/1 R, 29/157 R, 431/99 [51] Int. Cl. F23b 7/00 [58]Field of Search 110/1 R; 431/99;

[56] References Cited UNITED STATES PATENTS 3,460,223 8/1969 'Berczes etal 110/1 X 3,500,774 3/1970 Meier 110/1 3,570,419 3/1971 Brandenberger431/99 X Primary Examiner-Kenneth W. Sprague Attorney-Flynn & Frishauf[57] ABSTRACT A thermic lance which is operated by gaseous combustionand serves for forming openings, cavities or grooves in hard materialsuch'as concrete, stone, building walls and the like. The lance isequipped with a steel tube packed with a plurality of steel rods. Oxygenis passed through the tube from one end and the lance is ignited at theother end to produce an intense heat source that is applied to thematerial to be cut. Both the tube and rods become consumed duringburning out process. The enclosing tube has with the exception of itsends a cross-sectional shape which is other than circular. For securingthe rods in the tube a flat arcuate divergence is provided in the tubeand the rods near the gas connecting end part of the lance. Formation ofthe divergent zone and deformation of the tube in a noncircularcross-sectional shape is effected simultaneously by a single pressoperation.

13 Claims, 3 Drawing Figures PATEI JUEH 2 mm Fig. 7

THERMIC LANCE The present invention relates to a thermic lance which isoperated by gaseous combustion and serves for forming cavities, groovesor openings in hard material such as concrete, stone, building walls,severing reinforced concrete, hard to clear material and the like.

In my prior U.S. Pat. No. 3,570,419 I have described a thermic lancehaving a tubular shell, a number of core wires located inside thistubular shell and an oxygen connection at the end of the shell remotefrom the burning point, and also interspace running longitudinallybetween the core wires and the tubular shell for the conveyance of theoxygen. The disclosure of my prior U.S. Pat. No. 3,570,419 isincorporated herein by reference. Now as an improvement over theaforementioned patent, the present invention relates to a method andmeans for better securing the core wires in the surrounding tubularshell.

Thermal lances are subject to vibrations during the burning out process.As a result, that the core wires when held only by friction may somewhatalter their mutual locations, and may become somewhat loosened withinthe tubular shell. Moreover the oxygen pressure, which normally is up tosome 110 to 220 psi, acts upon the face of the core wires at the end ofthe lance which is remote of the burning point. It may happen that forexample a single wire becomes loose from the corewire group and be movedin the direction of the flow of the oxygen gas.

A loose wire may burn more quickly away than the others or may beejected when the break-through of the wall occurs or when the lance iswithdrawn from the opening. But as soon as one of the core wires islacking, the remaining wires also become loose within the tubular shell,so that finally the whole group or parcel of core wires no longer hasany anchorage in the tubular shell.

It is therefore a first object of the present invention to provide meansto securely hold all core wires within the tubular shell so that theycannot become loose and leave the tubular shell, even under strongvibrations occuring during the burning process.

A further object of the present invention is to provide a method formanufacturing thermal lances in a highly efficient manner.

The invention will be better understood and objects other than those setforthabove, will become apparent, when consideration is given to thefollowing detailed description thereof. Such description makes referenceto the annexed drawing in which:

FIG. I is a plan view of the end zone of a lance,

FIG. 2 is a section through the circular part of the thermic lance alongthe line [I II of FIG. 1, and

FIG. 3 is a section through the oval part of the ther- -mic lance alongthe line III III in FIG. 1.

The thermic lance 1 serves for the production of bores, apertures oropenings in concrete, rock, stone walls, mineral material or other hardmaterial, by means of a burning process. The flame for cutting isobtained by a method in which oxygen of high purity is blown underpressure through a tubular shell filled with wires from one end to theother and the front end of the lance is brought up to ignitiontemperature. In this way combustion is initiated and developed at thisend of the lance by a self-supporting thermal reaction with such anevolution of heat that concrete, rock and similar materials are fusedand the combustible material is burnt. In doing this the thermic lanceitself is successively consumed and must be replaced from time to time.

The thermic lance incorporates a tubular shell 2 of unalloyed steel(iron), usually several meters long; it may be a usual commerciallyavailable gas wire. Core tube 3 of round section and equal thickness toone another of unalloyed steel (iron) are drawn into this tubular shell2, and the number of these core wires 3 is so chosen that they fill theclearance section within the round enclosing tube or tubular shell 2 aswell as possible, but without making the drawing of these core wires 3into the tubular shell difficult. In practice a tubular shell 2 with aninside diameter of one-half inch and 11 core wires has provedsatisfactory. These core wires 3 advantageously consist of commercialstructural steel used for example for reinforced concrete. There remainbetween the individual wires 3 and between the wires and the internalwall of the tubular shell interspaces or ducts 5 running longitudinallyfor the passage of the oxygen.

The tubular shell 2 is provided at each end with a short external thread4, so that on the one hand two such tubes can be joined together by acoupling sleeve screwed onto them and on the other hand the other end ofthe tube can be connected to a hose which is connected in its turn to asource of oxygen under pressure.

After the core wires 3 have been drawn into the inside of the circularsection tubular shell 2, shell 2 is compressed to an oval over its wholelength, with the exception of both end pieces about 5 to 12 cm long. Inthis way the internal section of the tube is deformed and with it alsothe section of the duct 5 for the passage of the oxygen running throughit longitudinally parallel to the core wires. It is apparent that asectional ratio of the total metal area that is, the tubular shell plusthe core wires to the sectional area of the duct 5 for the passage ofthe oxygen should desirably be about I 9 to l 16. It has been found thatparticularly economical working is possible if the ratio of the crosssections of the surface of the enclosing tube 2 and of the total surfaceof the core rods lies between 1.4 l and l 1. It is desirable todistribute the duct area 5 as well and as uniformly as possible over thewhole sectional area of the tubular shell in order to ensure a uniformburning of the lance. Through the reduction of the duct sectional areafor the oxygen as a consequence of the deformation of the tubular shellto an oval, a better bunching of the burning jets results. In additionin this way the oxygen consumption is reduced, the heat is moreconcentrated and the smoke emission is reduced.

The core wires 3 according to my U.S. Pat. No. 3,570,419 are held insidethe tubular shell 2 as a result of the deformation of the tubular shellto an oval shape entirely by the clamping effect or, in other words, bythe friction of the wires one with another and on the inner wall of thetube.

In order to avoid individual core wires being able to become loose as aresult of the vibration occuring during the burning out process, a flatarcuate divergence 6 or curvature is imparted to the tubular shell 2 andthus to the core wires 3 located within it, as can be seen from FIG. 1.This divergence 6 is located at the gasconnection end in the oval partor otherwise deformed part, near one end of the lance. The insidesectional shape of this slightly curved or arched part should remain asfar as possible unaltered in relation to the neighbouring oval part, sothat the ducts for the passage of the oxygen are not restricted insection in this curved zone. The length a of the tubular shell 2 with acircular sectional shape is about the same length as the chord length 0of the curved part 6. The oval zone b lying between these isconsiderably shorter than the lengths a or c and preferably amounts toabout one half or rather less. The chord length c is preferably aboutfour to six times the outside diameter of the tubular shell 2 in thecircular part.

As a result of the arcuate divergence 6, it is no longer possible forthe core wires 3, even if they should become loose in the course of theburning out process, to be individually released from the tubular mantleor shell 2, since the core wires 3 take on the same curved form as thatof the tubular shell 2 surrounding them.

The divergent zone 6 is flat, that is, the height h of this zone issmall in relation to the section dimensions of the tubular shell 2; itis smaller than the outer diameter of the round tubular shell at theconnection ends. Preferably the height of the divergent zone H onesixthto one-half of the external diameter of the tubular I shell 2 in thecircular connection zones.

When the part of the lance departing from a circular section has an ovalform, the divergent zone is effected upon the flat side of the oval;that is, the arcuate divergence is produced flat-edged and nothigh-edged.

So that it may not matter which of the two ends of the lance is used forthe oxygen connection, it is also possible to provide the divergent zone6 described on both end zones of the lance.

It would further be possible to introduce on the divergent zone 6 asvisible in FIG. 1 at least a second, directly adjacent divergent zonecurved in the same or in the opposite direction, so that in this way aflat wave form results. In this way it is possible to employ even asmaller divergence height in the individual divergent zones, but thesectional shape in the waved zone should be as equal as possible to thatof the principal or middle part of the lance.

Manufacturing of such thermic lances is effected by first drawing such anumber of core wires 3 into atubular shell 2 having a round section overthe whole length that the section is filled as well as possible.Thereafter the tubular shell 2 together with the 'core wires 3 itcontains is with the exception of at least one end compressed in a pressin a single action into an oval form, and simultaneously the arcuatedivergence 6 already described imparted to the lance. Since theformation of the divergent zone-occurs simultaneously both in thetubular shell and also in all core wires in a single operation, thismethod of manufacture is particularly economical.

Instead of shaping or deforming the tubular shell into an oval sectionalshape, it is also possible that this tubular shell may be caused toassume cross-sectional shapes other than circular, for example atriangular, polygonal, half-round or other shapes, and the divergentzones 6 are provided in a similar manner, where here also it is ensuredthat the sectional shape in the divergent zone is as equal as possibleto that of the sectional shape departing from a circular form in theprincipal part of the lance, in order to avoid a contraction of theoxygen ducts in the divergent zone 6.

It will be understood that the present invention is not limited to thespecific materials, steps and other specific details described above andmay be carried out with various modifications without departing from thescope of the invention as defined in the appended claims.

I claim:

1. Thermic lance for gaseous combustion for forming cavities, grooves oropenings in hard material such as concrete, stone, building walls,comprising a metallic tube, and a plurality of metallic rods enclosed bysaid tube, said tube having gas connecting means at one end,intermediate spaces being formed between said rods and between said rodsand said tube extending in the longitudinal direction of said tubeserving for the conveyance of gas for combustion, and said tube having across-sectional shape other than circular except at least one of its endparts, in the vicinity of said gas connecting means said tube and saidrods having at least one relatively flat divergence for securing saidrods in said tube.

2. Thermic lance as defined in claim 1 wherein the divergent zone islocated in the part of the tube the cross-sectional shape of whichdeparts from the circular shape.

3. Thermic lance as defined in claim 1 wherein the part of the lancedeparting from a circular shape has an essentially oval shape incross-section, the divergent zone being formed upon the flat side of theoval.

4. Thermic lance as defined in claim 1 wherein the tube hassubstantially the same sectional form in the divergent zone as in thepart of the lance departing from the circular shape.

5. Thermic lance as defined in claim 1 wherein the height (h) of thedivergent zone is smaller than the external diameter of the tube in saidend part.

6. Thermic lance as defined in claim 1 wherein the height (h) of thedivergent zone is smaller than half the external diameter of the tube insaid end part and the chord length (0) of the divergent zone amounts tofour to six times the external diameter of said end part of said tube.

7. Thermic lance as defined in claim 1 wherein said divergence zone hasthe form of a wave.

into a shell having a circular cross-sectional shape, giving the shellan oval shape over the whole length except at least one of its endparts, forming at least one arcuate divergence in said shell and thecore wires in the vicinity of one of said end parts, said oval shape andsaid arcuate divergence being formed simultaneously in a single pressingoperation.

9. Thermic lance for gaseous combustion for forming cavities, grooves oropenings in hard material such as concrete, stone, building walls,comprising an essentially straight metallic tube having end parts and anintermediate part, and a plurality of metallic rods located within andenclosed by said tube, said tube having gas connecting means at least atone end part, intermediate spaces being formed between said rods andsaid tube extending in the longitudinal direction of said tube servingfor the conveyance of gas for combustion, and

said tube, in the vicinity of said gas connecting means, having at leastone relatively flat divergence from the straight axis of the tube forsecuring said rods in their location in said tube and prevent looseningof said rods in said tube.

height (h) of the divergent zone is smaller than half the externaldiameter of the tube in said end part and the chord length (a) of thedivergent zone amounts to four to six times the external diameter ofsaid end part of said tube.

13. Thermic lance as defined in claim 9, wherein said divergence zonehas the form of a wave.

III IF t UNITED STATES PATENT UFFICE CERTIFICATE OF 'CORRECTIGN PatentNo. 3,738,288 Dated June 12 I973 Inventor s) Erns t BRANDENBERGER It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

On the initial page of the patent, change the Assignee to read:

Kubatec Kunststoffund Bautechnik AG Triesen, Liechtenstein--.

Signed and sealed this 3th day of April 1975.

SEAL) fattest:

C. E'LARSFALL DANN ON Commissioner of Patents rflcer and Trademarks RUTHC. WAS attesting O 1 FORM PC4050 USCOMM-DC 60376-P89 i ".5. GOVERNMENTPRINTING OFFICE I969 0-366-334,

1. Thermic lance for gaseous combustion for forming cavities, grooves oropenings in hard material such as concrete, stone, building walls,comprising a metallic tube, and a plurality of metallic rods enclosed bysaid tube, said tube having gas connecting means at one end,intermediate spaces being formed between said rods and between said rodsand said tube extending in the longitudinal direction of said tubeserving for the conveyance of gas for combustion, and said tube having acrosssectional shape other than circular except at least one of its endparts, in the vicinity of said gas connecting means said tube and saidrods having at least one relatively flat divergence for securing saidrods in said tube.
 2. Thermic lance as defined in claim 1 wherein thedivergent zone is located in the part of the tube the cross-sectionalshape of which departs from the circular shape.
 3. Thermic lance asdefined in claim 1 wherein the part of the lance departing from acircular shape has an essentially oval shape in cross-section, thedivergent zone being formed upon the flat side of the oval.
 4. Thermiclance as defined in claim 1 wherein the tube has substantially the samesectional form in the divergent zone as in the part of the lancedeparting from the circular shape.
 5. Thermic lance as defined in claim1 wherein the height (h) of the divergent zone is smaller than theexternal diameter of the tube in said end part.
 6. Thermic lance asdefined in claim 1 wherein the height (h) of the divergent zone issmaller than half the external diameter of the tube in said end part andthe chord length (c) of the divergent zone amounts to four to six timesthe external diameter of said end part of said tube.
 7. Thermic lance asdefined in claim 1 wherein said divergence zone has the form of a wave.8. A method for manufacturing a thermic lance comprising the steps ofintroducing a plurality of core wires into a shell having a circularcross-sectional shape, giving the shell an oval shape over the wholelength except at least one of its end parts, forming at least onearcuate divergence in said shell and the core wires in the vicinity ofone of said end parts, said oval shape and said arcuate divergence beingformed simultaneously in a single pressing operation.
 9. Thermic lancefor gaseous combustion for forming cavities, grooves or openings in hardmaterial such as concrete, stone, building walls, comprising anessentially straight metallic tube having end parts and an intermediatepart, and a plurality of metallic rods located within and enclosed bysaid tube, said tube having gas connecting means at least at one endpart, intermediate spaces being formed between said rods and said tubeextending in the longitudinal direction of said tube serving for theconveyance of gas for combustion, and said tube, in the vicinity of saidgas connecting means, having at least one relatively flat divergencefrom the straight axis of the tube for securing said rods in theirlocation in said tube and prevent loosening of said rods in said tube.10. Thermic lance as defined in claim 9, wherein the tube hassubstantially the same sectional form in the divergent zone as in thepart of the lance remote from the gas connecting means.
 11. Thermiclance as defined in claim 9, wherein the height (h) of the divergentzone is smaller than the external diameter of the tube in said end part.12. Thermic lance as defined in claim 9, wherein the height (h) of thedivergent zone is smaller than half the external diameter of the tube insaid end part and the chord length (c) of the divergent zone amounts tofour to six times the external diameter of said end part of said tube.13. ThermIc lance as defined in claim 9, wherein said divergence zonehas the form of a wave.